Purpose: Accurate interpretation of cardiorespiratory fitness (CRF) requires reference values that account for sex, age, and body composition. Existing reference values often lack these distinctions or exclude older adults. This study aimed to establish sex- and age-specific reference values for absolute and relative (body mass-corrected and lean body mass-corrected) CRF parameters derived from cardiopulmonary exercise testing (CPET) in Dutch community-dwelling 55- to 75-year-old adults. Methods: Cross-sectional data from 611 participants of the AMCOHF study were analyzed. CRF was assessed via cycle ergometer CPET evaluating oxygen uptake (V̇O_2peak) and work rate (WR_peak) at peak exercise, oxygen uptake at the ventilatory anaerobic threshold (V̇O_2VAT), and oxygen uptake efficiency slope (OUES). Body mass and lean body mass were measured using dual-energy X-ray absorptiometry. Reference values stratified by sex and age were developed using generalized additive models. Prediction equations were generated using multiple linear regression. Correlations with V̇O_2peak assessed the usefulness of V̇O_2VAT and OUES as submaximal and effort-independent alternatives for CRF. Results: All CRF variables declined with age. V̇O_2peak (L/min) declined quasi-linearly (females: 1.3%/year; males: 2.5%/year). Significant sex differences were observed between all CRF variables (absolute and body mass-corrected values: p < 0.001; lean body mass-corrected values: p < 0.05). Significant correlations were found between V̇O_2peak and WR_peak (ρ = 0.90), V̇O_2VAT (ρ = 0.78), and OUES (ρ = 0.87). Conclusion: This study provides reference values for V̇O_2peak, WR_peak, V̇O_2VAT, and OUES in Dutch older adults aged 55–75 years during cycle ergometer CPET, offering a unique dataset for assessing CRF and monitoring intervention effects.

Introduction: Frailty, characterized by a reduction in intrinsic capacity across multiple physiological systems, is a key concern in healthy aging. Insight in the trajectory of an individual’s functional ability and intrinsic reserve capacity in a relatively younger population of older adults is lacking. This study aims to investigate the early stages of frailty by tracking trajectories of physical indicators of intrinsic capacity before frailty becomes clinically evident. Methods: The AMersfoort COhort study on functional decline, Healthy aging and Frailty (AMCOHF) is a unique 10-year prospective cohort study evaluating the predictive value of longitudinal trajectories of physical parameters for frailty onset or robustness maintenance. An a-select community-dwelling robust population of Amersfoort (55–75 years) in the Netherlands will undergo baseline assessments for inclusion criteria and will be followed longitudinally every 2.5 years. Frailty status is assessed using the Fried phenotype, Rockwood frailty index, and Groningen frailty indicator. Testing procedures and questionnaire completion include physical performance tests in the domains: (1) musculoskeletal system, (2) articular system, (3) cardiorespiratory system, (4) sensory system, (5) immune system, and 6) uro-gynecological system. Study outcomes focus on intrinsic capacity, functional ability, explanatory data, and frailty. Statistical analyses evaluating the predictive capacity include logistic regression, confirmatory factor or latent class analysis, and structural equation modeling. Nonprobability convenience sampling recruits 2,078 robust participants, estimating a 1-year frailty incidence of 1.5%–6.0%. Ethical approval was obtained, and the trial is prospectively registered on Open Science Framework (DOI: 10.17605/OSF.IO/RMBQV). Conclusion: The AMCOHF study will contribute to knowledge about markers to predict an accelerated decline in intrinsic capacity in an early stage. This knowledge is important to deploy prevention strategies at an earlier stage in life then those currently undertaken, ultimately reducing healthcare costs and contributing to a healthy aging population.

As a safer alternative for the use of radioactive tracers, the enriched stable 58Fe isotope has been introduced in studies of iron metabolism. In this study this isotope is measured with instrumental neutron activation analysis (INAA) in blood samples of patients with iron related disorders and controls after oral ingestion of a 58Fe containing pharmaceutical. Results were compared with those derived from MC-ICP-MS, applied on the same samples, and analytical and practical aspects of the two techniques were compared. Both techniques showed an increased absorption and incorporation in red blood cells of the 58Fe isotope in iron deficient patients in contrast to the controls. In all individuals results of INAA measurements were in good agreement with those of MC-ICP-MS ( |zeta| < 2 ). Uncertainties in INAA are substantially higher than those achievable by MC-ICP-MS but the INAA technique offers a high specificity and selectivity for iron close to 100%. In contrast to INAA, sample preparation before measurement is very critical in MC-ICP-MS and interferences with 58Ni and 54Cr may hamper the measurement of 58Fe and 54Fe respectively. Since it takes at least five days after irradiation to reduce the activity of interfering radionuclides (mainly 24Na), INAA is a more time consuming procedure; the need of a nuclear reactor facility makes it also less accessible than MC-ICP-MS. Costs are comparable. Both INAA and MC-ICP-MS are able to adequately measure changes in iron isotope composition in blood when an enriched stable iron isotope is applied in clinical research. Although MC-ICP-MS is more sensitive, is faster and has easier access, in INAA preparative steps before measurement are simpler and there are hardly demands on the kind and size of the samples. This may be relevant working with biomaterials in a clinical setting.

Low concentrations of elements in food can be measured with various techniques, mostly in small samples (mg). These techniques provide only reliable data when the element is distributed homogeneously in the material to be analysed either naturally or after a homogenisation procedure. When this is not the case or homogenisation fails, a technique should be applied that is able to measure in samples up to grams and even kilograms and regardless of the distribution of the element. An adaptation of neutron activation analysis (NAA), called large-sample NAA, has been developed and proven accurate and may be an attractive alternative in food research and mass balance studies. Like standard NAA, large-sample NAA can be used to measure both toxic and trace elements relevant for nutrition.

Although cycling has positive health effects, including improvement of cardiovascular fitness, it does not have a favourable effect on bone health. In professional cyclists, the bone mineral density (BMD) will actually have decreased at the end of an intensive season. As a professional cyclist's career progresses, there will be a further decrease in BMD particularly in the hip and lumbar spine. The forward leaning position, the repetitive movement at low intensity, and the fact that body weight is carried by the bicycle all contribute to non-stimulation of bone formation. The cyclists' low body weight, which is desirable for climbers in particular, and possibly their dietary pattern may exacerbate this negative effect. To reduce the risk of fractures both during and after a cycling career, it is desirable that more attention is paid to strengthening of the bones. The effectiveness of training programmes to strengthen the bones should be investigated in carefully designed research studies.

Accurate assessments of the iron (Fe) intake from food is mandatory for mass balance studies. The reliability of such assessments is strongly dependent on the representativeness of the analytical test portion and, as such, the quality of the homogenization of the double portions collected. Large sample Instrumental Neutron Activation Analysis (INAA) circumvents these problems as the entire double portions can be analysed without homogenization.
Fe was measured both in approximately 1 kg freeze-dried food as well as in moist products. A (commercially available) porridge fine wheat grain was used as a reference sample (assumed to be homogeneous in the Fe content). The amount of iron in the fine wheat grain was also measured using small sample INAA. The moisture content of the fresh food did not cause any problem during the irradiation such radiolysis and excessive gas formation due to low radiation dose during the irradiation. The results obtained for the moist sample were statistically equivalent to those found for the dried sample ( 73.1± 4, 74± 3 mg/kg respectively, zeta (ζ ) score = 0.18) . The applicability of LS-NAA was further illustrated by measurement of Fe in commercially available microwave meals which was found to be 30±2 mg/kg. Large Sample INAA is a novel and attractive approach for measurement of element content of the dietary intake by the double portion technique collected during 5-7 day in mass balance experiments. Similarly, it can be directly applied without sample preparation for the analysis of faeces collected in such studies.

Iron deficiency anaemia is a major health problem worldwide, but may be complicated in underdeveloped nations by deficiencies of other micronutrients with consequences for adequate treatment. The World Health Organization (WHO) estimates that 2 billion people – over 30% of the world’s population – are anaemic, approximately 50% of cases of anaemia are considered to be due to iron deficiency. Aim: Since a combined deficiency of trace elements has great consequences in the approach of this problem, zinc status was assessed in blood of iron deficient anaemic patients in Sudan representing sub-Saharan Africa and compared with Dutch anaemic patients representing Western Europe. Method: Zinc as well as iron were measured with instrumental neutron activation analysis (INAA) in 22 Sudanese anaemic patients and four controls as well as in 17 Dutch anaemic patients and four controls. Result: In the Sudanese patients very low concentrations of zinc were measured, 3 ± 1 mg/L compared to a control group of healthy individuals (5 ± 1 mg/L), while all Dutch patients had normal zinc levels (5 ± 1 mg/L). When matched for haemoglobin level, the Sudanese patients still showed lower zinc concentrations. Even in the Sudanese patients without a known history of malnutrition and in patients with the anaemia of chronic disease zinc levels were significantly lower than in the controls. A positive correlation was observed between Fe and Zn in blood of the Sudanese subjects (r=0.654), while there is no or a very week relation between Fe and Zn in blood of the Dutch group (r=0.08). The low level of Fe and Zn for the Sudanese group might be ascribed to the poor intake of these two nutrients with the main dietary food (cereals) in this area. Conclusion: In iron deficiency anaemia in Sudanese patients, a deficiency of zinc should be taken into account in case of supplementation.

Background Wernicke encephalopathy can have different clinical outcomes. Although infections may precipitate the encephalopathy itself, it is unknown whether infections also modify the long-term outcome in patients developing Korsakoff syndrome. Objective To determine whether markers of infection, such as white blood cell (WBC) counts and absolute neutrophil counts in the Wernicke phase, are associated with cognitive outcomes in the end-stage Korsakoff syndrome. Method Retrospective, descriptive study of patients admitted to Slingedael Korsakoff Center, Rotterdam, The Netherlands. Hospital discharge letters of patients with Wernicke encephalopathy were searched for relevant data on infections present upon hospital admission. Patients were selected for further analysis if data were available on WBC counts in the Wernicke phase and at least 1 of 6 predefined neuropsychological tests on follow-up. Results Infections were reported in 35 of 68 patients during the acute phase of Wernicke-Korsakoff syndrome—meningitis (1), pneumonia (14), urinary tract infections (9), acute abdominal infections (4), sepsis (5) empyema, (1) and infection “of unknown origin” (4). The neuropsychological test results showed significant lower scores on the Cambridge Cognitive Examination nonmemory section with increasing white blood cell counts (Spearman rank correlation, ρ = −0.34; 95% CI: −0.57 to −0.06; 44 patients) and on the “key search test” of the behavioral assessment of the dysexecutive syndrome with increasing absolute neutrophil counts (ρ= −0.85; 95% CI: −0.97 to −0.42; 9 patients). Conclusions Infections may be the presenting manifestation of thiamine deficiency. Patients with Wernicke-Korsakoff syndrome who suffered from an infection during the acute phase are at risk of worse neuropsychological outcomes on follow-up.